Timing adjusting apparatus for internal combustion engines



Jan. 16, 1968 R. s. M cREA TIMING ADJUSTING APPARATUS FOR INTERNAL COMBUSTION ENGINES.

2 Sheets-Sheet 1 Filed Sept. 24, 1964 IL I] 'll ADJUSTABLE DELAY UNIT 10) TIMING SELECTOR REMOTE CAR A P 2. Q ga l A I l 20 gin?) INVENTOR.

4 FIG 4 47'ZOP/I/EV R. S. M CREA TIMING ADJUSTING APPARATUS FOR INTERNAL COMBUSTION ENGINES I I I l i 1 I l l I l l I l l J E C m V D A Jan. 16, 1968 United States Patent 3,364,418 TIMING ADJUSTENG APPARATUS FOR INTERNAL CGMBEUS'HON ENGENES Richard {5. MacCrea, New lirighton, Minn, assiguor to Marquette Corporation, Minneapolis, Mind, 21 corporation of Delaware Filed Sept. 24, 1964, Ser. No. 393,985 6 Claims. (Cl. 324--ll6) ABSTRACT OF THE DISCLQSURE Apparatus for remotely adjusting the timing of an internal combustion engine in which a pulse from the ignition circuit breaker is adjustably delayed by a two-stage timer, before application to a spark plug, through a time period which may vary from less than to greater than the normal time period between successive ignition pulses.

One common method employed in adjusting the timing of the electrical ignition of an internal combustion engine is to mechanically rotate the distributor while observing the results on a dynamometer or other engine testing device. This procedure of mechanically shifting the position of the distributor while the engine is running can be quite hazardous at times.

It is an object of the present invention to provide an arrangement where the ignition timing can be varied remotely for testing purposes. Very generally, I accomplish this by interposing a delay device between the normal source of ignition pulses and the distributor, this delay device being capable of introducing a delay comparable to the normal time between pulses so that the pulse actually supplied to the spark plug or other igniting device is the result of the next succeeding pulse as compared with the one which normally would be applied to that particular plug. By introducing such a delay device and providing for adjustment of the delay device, it is possible by varying the amount of delay to advance or retard the ignition any desired amount simply by varying the extent of this delay. In this way, the optimum timing setting can be conveniently and safely determined so that the proper adjustment can subsequently be made while the engine is not running.

A further object of the invention is to provide such a device capable of being used with internal combustion engines having different numbers of cylinders and operated at different speeds so that regardless of the number of cylinders of the engine or the speed at which the englue is operated, the delay device can be adjusted to provide the appropriate delay necessary to shift the timing of the applied pulse by approximately the amount of time existing between pulses.

Another object of the present invention is to provide such a device in which there is an indication of the amount of timing displacement that has been produced with respect to the timing between pulses to indicate the extent to which the ignition has been eiiectively advanced or retarded.

A still further object of the present invention is to provide such an arrangement in which there is calibrating means for the indicating means operative when actuated to cause the time delay produced by the timing control apparatus to exactly equal that normally existing between two pulses.

A further object of the present invention is to provide a timing device applicable to any source of a series of pulses to adjustably delay the pulses over a range which may vary from less than to greater than the time between pulses.

A further object of the present invention is to provide apparatus for delaying a pulse by an amount which is equal to the sum of two separate delay periods with means for simultaneously adjusting the length of each delay period and further means for individually adjusting the length of one of said delay periods independently of the other.

Other objects of the invention will be apparent from a consideration of the accompanying specification, claims, and drawing of which:

FIGURE 1 is a schematic view of my ignition control apparatus showing it connected between the conventional ignition coil and distributor;

FIGURES 2, 3 and 4 are schematic figures showing the angular phase relationship between the ignition pulse produced by the delay device and the normal position of the pulse from which it is derived as well as the relationship wiih respect to the desired position of the pulse; FIGURE 2 specifically deals with the case where the ignition pulse applied by the delay device is applied at.

exactly the same time to a spark plug as though no delay had been introduced; FIGURE 3 deals with the case where the delay is slightly less than the time normally existing between pulses sothat the application of the voltage pulse to the plug to be fired is actually advanced; and FIGURE 4 deals with the case where the delay is greater than that normally existing between pulses so that the timing of the pulse is retarded;

FIGURE 5 is a schematic view showing the circuit details of my delay device; and

FIGURE 6 is a schematic view showing a portion of the components of FIGURE 5 rearranged to show the action of a meter indicating the extent: the timing has been advanced or retarded.

Referring to the drawing, I have shown my delay unit 10 as connected between the secondary winding 11 of a conventional ignition coil 12 and the rotor arm 14 of a conventional distributor is.

Basically, the ignition means employed in connection with a conventional internal combustion engine comprises a voltage pulse producing means and a distributor for applying this voltage pulse producing means to plugs or other igniting devices in the desired order. The timing is adjusted by rotating the distributor which varies both the phase position in which the pulses are formed and that in which they are applied to the respective plugs. Even with my apparatus, the actual adjustment is made in this manner. Initially, however, my apparatus enables a mechanic to determine how much the timing should be adjusted so that the actual adjustment can subsequently be made with the engine not running, or running at idle speed.

Reference has already been made to the secondary 11 of the ignition coil 12. This ignition coil 12 is of conventional construction and comprises, in addition to the high voltage secondary winding 11, the conventional core and a low voltage primary winding 13. This primary winding 13 is connected through a switch: 16, which may be the ignition switch of the automobile, to the positive terminal of a conventional automobile battery 17, the negative terminal of which is connected to ground at 18. The terminal of primary winding 13 opposite to that which is connected to the switch 16 is connected to the movable switch blade 20 of the conventional ignition circuit breaker. This movable switch blade 20 cooperates with a fixed switch blade 21, being moved into and out of contact-making engagement with switch blade 21 by a rotating cam 22;. The cam 2.2 is provided with a plurality of high points equal in number to the number of cylinders in the internal combustion engine. In the example employed in the present case, I have illustrated the invention as employed in connection with a fourcylinder engine for simplicity. It will be noted that the cam 22 has four high points so that for each revolution of cam 22, the circuit breaker switch blade 29 is separated from fixed switch blade 21 four times. Connected across the two switch blades Zll and 21 is the conventional capacitor 24 to minimize arcing across the contacts of switch blades 29 and 21. The left-hand end of switch blade 21 is connected to ground at 25.

When the ignition switch 16 is closed, a circuit exists from the positive terminal of battery 1') through tne primary winding 13, switch blades 20 and 21, ground connections and 18, back to the negative terminal of battery 17. This circuit exists when switch blades 20 and 21 are in contact. When the cam 22 rotates to the position shown, however, this flow of current through primary winding 13 and switch blades 20 and 21 is abruptly terminated, causing an abrupt change in the current flowing through primary winding 13. This, in turn, produces a voltage pulse across high voltage secondary winding 11, which, when the engine is connected normally is connected directly to the distributor.

Turning now to the distributor, I have shown schematically four spark plugs 23, 29, and 31, each having one terminal connected to ground. In the conventional internal combustion engine, this is done simply by aving one of two electrodes connected to the shell which, in turn, is in engagement with the engine casting. The spark plugs 28-31 can be associated with the engine cylinders 1-4, respectively, of a iour-cylinder internal colubustion engine.

The function of the distributor 15 is to apply the voltage pulses to the correct spark plug at the proper time and in the correct sequence. The distributor 15, as previously noted, comprises a movable switch arm 1 2i which successively engages a plurality of contacts 32, 33, 34 and 35. It will be noted that contacts 32, 33, 34 and are not connected in the same order to spark plugs 283l. The reason for this is that it is conventional in an internal combustion engine to fire the cylinders in a difierent order from the manner in which they are located in the engine so as to give a better balance to the operation of the engine. Thus, contact 32 is connected to spark plug 28 associated with cylinder No. 1, the next distributor contact 33 is connected to spark plug 36 associated with cylinder No. 3. The next distributor contact 34- is connected to spark plug 31 associated with cylinder No. 4 and the final distributor contact 35' is connected to spark plug 29 associated with cylinder No. 2. Thus, the distributor functions to cause the cylinders to fire in the following order: 1342.

Since the provision of a delay device which will transmit the high voltage impulse required for ignition completely through the delay unit would be prohibitively expensive, the high voltage impulse produced by the ignition coil 12 is reduced to a relatively small voltage in the delay device and is used to trigger and accelerate ignition coil having a primary winding 41 and a secondary winding 4-2, the lower terminals of the two windings being connected together and to ground at 43. The ungrounded terminal of high voltage secondary winding 42 is connected through a conductor 45 to the distributor arm 14 so that the voltage output from the ignition coil 49 is applied to the distributor arm just as is the high voltage output of coil 12 when the ignition apparatus is operating in the normal manner without my improved delay apparatus.

in FIGURES 2, 3, and 4, I have shown the effect of introducing the delay. These figures show in phase diagram fashion, the effect of the delay introduced. The numerals It, 3, 4 and 2 extending around the periphery of each figure represent the cylinder numbers. T dotted line extending from the center of each figure to the points marked it and 3 represent two positions of the distributor arm. The solid line with an arrow represents the phase position of the spark actually applied.

purposes of Turning to HGURE 2, there is depicted the condition when the spark is delayed by the exact amount of time occurring between successive pulses or, in other words, by a phase angle corresponding to the angle or" movement of the distributor arm existing between the firing of the spark plugs in successive cylinders. It has been as sumcd that the engine is a four-cylinder engine and that this phase angle is degr es. it will be noted that the sofid line depicting the pos on of the actual spark pulse is in phase with the distributor arm as it extends to the plug of cylinder 3. This pulse is actually the pulse in tended for cylinder 1 but since it has been delayed 90 degrees, it is applied to the distributor just as the distributor reaches the position at which spark plug No. 3 is to be fired. The spark plug and distributor, or" course, are not affected by the source of the pulse and as far as they are concerned, the operation is exactly the same as though the original pulse normally generated at the time that the distributor arm reaches the position for the firing of the spark plug of cylinder No. 3 had been applied to the distributor arm.

in FIGURE 3 the angle of displacement of the spark with respect to its original phase position is less than 90 degrees, for example, '75 degrees. Under these conditions, the spark occurs 15 degrees before the normal time called for by the distributor for the firing of the spark plug of cylinder No. 3. in other words, the firing is advanced 15 degrees.

In FIGURE 4, I have shown a phase displacement angle of greater than 90 degrees, for example, degrees. Under these conditions, the firing is retarded by 15 degrees with respect to where it would normally have occurred.

Referring now to my delay unit 10, this is provided with a meter 59 which is calibrated to indicate the degrees of retard or advance, as will be described in more detail. I have also provided a range selector knob 51, the function of which is to adjust the timing delay so that it is approximately equal to that existing between the pulses of the ignition voltage. Thus, in a six-cylinder automobile, the range selector will be adjusted to provide a time delay corresponding to a 60 degree delay. In an eight-cylinder automobile, the delay will be 45 degrees and, as pointed out above, in a four-cylinder car the delay will be 90 degrees. The actual delay time will depend not only upon the number of cylinders but also upon the speed at which the test is to be run. Thus, the setting of knob 51 will be determined by the number of cylinders and the engine test speed. The knob 52 is provided for further adjusting the ignition to provi e the desired retarding or advance for the selected engine and engine speed. A knob 53 is provided for initially adjusting the calibration of the meter as will be explained in more detail. I also have provided a timing selector 54 which has two positions in one of which the ignition timing is exactly that provided by the car without the interposed delay whereas in the remote position with which my delay unit is normally used, the ignition pulse actually applied to the distributor is displaced by the desired angle from the original pulse. i also provide a knob 55 controlling a push-button switch. When the button is depressed, the phase displacement produced by the apparatus is exactly equal to the angular phase relationship between the original pulses. The meter adjustment knob 53 can be adjusted at that time so as to read zero since with the delay unit connected and operative, there should under these conditions be no shifting of the ignition timing. I further provide an on-orf switch 56 which will likewise be referred to later.

Before proceeding with the details of my delay unit. the overall operation of the system will now briefly be reviewed. The normal connection between the ignition coil 12 and the distributor 15 is interrupted and my delay unit lit is interposed along with the auxiliary ignition coil From a table ch may be provided, listing different numbers of cylinders and diilercnt possible engine speeds, the range selector 51 is moved to the appropriate position to provide the desired amount of delay corresponding normally to the time existing between two successive pulses produced by the breaker switches 20 and 21. The knob 52 is adjusted to provide for the ignition being somewhat retarded. The button 55 is then depressed and the knob 53 is rotated until the pointer is exactly at zero. The automobile will have been associated with some testing device such as a dynamometer which can measure its performance. With the knob of timing selector 54 in the remote position, the ignition adjusting knob 52 is now adjusted so as to vary the timing of the ignition. What is being done at this time, as shown in FIGURES 3 and 4, is that the angle of delay is being adjusted so as to exceed or be less than the normal angle existing between two successive ignition pulses. The operation of the engine is observed as this knob is turned. When the optimum condition is obtained, the phase angle reading is noted on meter 55. Thereafter, my apparatus can be disconnected, and the distributor can be IO- tated through the angle which has been determined as the one necessary to obtain the optimum conditions. It will be seen that my apparatus enables the optimum timing setting to be quickly determined without the mechanic actually manipulating anything within the engine compartment while the engine is running.

FIGURE 5 While I have discussed the delay device in the above description as though it were a conventional delay device, my delay unit has a number of unique features.

There are various definite problems in connection with the delaying of the application of a high voltage spark for the substantial period of time existing between two pulses of an ignition coil. As pointed out above, I partially accomplish this by reducing the magnitude of the voltage involved to the point at which it can be handled by inexpensive low voltage electric components and use the resultant voltage to trigger a pulse amplifier which in turn controls the energization of the primary winding of an auxiliary ignition coil 40. Furthermore, I accomplish the relatively long period of delay necessary by providing two delay periods, one of which is initiated upon the termination or the first one, the total delay time being the sum of the delay times of the two delay periods. As will be pointed out below, these delay periods are adjustable toget-her'by one adjusting means and adjustable independently by another adjusting means. Furthermore, the delay time must always be related to the time between pulses, no matter what is the time spacing of the pulses.

Referring now to the details of the delay unit of Fl'G- URE 5, the voltage appearing across the secondary winding 11 of the ignition coil 12 is applied between the input terminal 60 and ground terminal 61 of the delay unit it). This voltage is applied across two relatively low resistors 62 and 63 having a relatively low resistance value as compared with the voltage. In one particular embodiment, as will be pointed out later, each of these resistors had a resistance value of 6.8 kilohms. The impedance of these two resistors is very low as compared with the impedance of a typical spark plug to which the secondary winding 11 is designed to be connected. As a result, there is considerable droop in the output voltage of the secondary 11 so that the voltage actually appearing across the terminals of resistors 62 and 63 is substantially less than the normal secondary voltage of winding 11.

The two capacitors 64 and 65 are connected in series with each other across the outer terminals of resistors 62 and 63 so that the voltage existing across these resistors is divided between capacitors 6'4 and 65, these two capacitors thus acting as a voltage divider. The capacitor 65 has a relatively high capacitance as compared with that of capacitor 64, so that the voltage drop appearing across capacitor 65 represents a relatively small portion of the total voltage drop appearing across resistors 62 and 63 in series. This, in turn, as was just mentioned, is substantially less than the normal voltage of secondary 11. Thus, the A.C. voltage appearing across capacitor 65, which is applied to the input of the timing circuit, is a relatively small portion of the total normal voltage output of secondary 11. A portion of the voltage appearing across capacitor 65 is applied to the base of a PN'P transistor 66.

Thc collector-emitter voltage of this transistor 66 is derived from a power supply 67 having its input connected to a secondary winding 68 of a transformer 69. The transformer 69 has, in addition to secondary winding 68, a primary winding 70, a relatively low voltage secondary winding 71, and a relatively high voltage secondary winding 72. The primary winding 70 is connected to input terminals 73 and 74, the on-otl switch 56, referred to in FIGURE 1, being connected between one terminal of primary winding 7% and power terminal 74. It is understood that power term'sals 73 and "M are adapted to be connected to any suitable source of commercially available power. r

The power supply :7 is of a conventional type having a rectifier, which may be a full wave rectifier, and various elements for filtering the rectified voltage to produce a relatively smooth DC. voltage at output terminals 78 and 79. The magnitude of the output voltage at terminals 78 andfl9 is maintained relatively constant by means of a Zener diode 86, one electrode or" which is connected by conductors 81 and 82 to the positive output terminal of the power supply and the other electrode of which is com nected by conductors 83, S4, and 35 to the negative terminal of the power supply. The Zener threshold voltage is chosen to correspond to the desired output voltage. in connection with transistor E6 and various other transistors employed in my delay unit, there is provided a positive bus conductor 86 which is connected to ground at 61. There is also provided a negative bus conductor $7. The positive or grounded bus conductor 86 is connected by conductors 88, 81, and 82 to the positive terminal of the power supply 67, while the negative bus conductor 87 is connected by conductors 84 and E5 to the negative terminal 79 of the power supply.

Turning back to the transistor 66 and the input voltage applied thereto by capacitor 65, the voltage appearing across capacitor 65 is applied across a resistor 90, which has its upper terminal connected through a diode 91 and a resistor 92 to the base of transistor 66. The lower terminal of resistor 90 is connected through bus conductor 86, diode and conductors 76, 7'7, and 94 to the emitter of transistor 66. Diode 75 acts to produce a voltage drop between emitter 66 and ground and serves to cut oil the transistor 66 when there is no base signal, as will be described. Connected between the lefthand terminal of resistor 92 and bus conductor 86 is a further resistor 95. The resistor has a relatively large resistance value as compared with the resistor 95. The resistors 90, 95, and the diode 91 act collectively to prevent anything but negative pulses from reaching the base of transistor 66 and for reducing the -magnitude of these negative pulses. It will be noted thatthe portion of the alternating voltage appearing across capacitor 65, which is positive with respect to the ground bus conductor 86, is blocked from passing through to the base of transistor 66 by diode 91. Hence, the entire positive portion of the voltage appears across resistor 90. Turning now to the negative portion of the alternating voltage appearing across capacitor 65, it will be noted that the current resulting from this portion of voltage has two possible paths. It may pass through the resistor 96, creating a voltage drop thereacross. It may also pass through the relatively low resistance 95 and the diode 91. Due to the relatively small size of resistor 95 as compared with resistor $9, the voltage drop appearing across 95 will be a relatively small portion of the total voltage appearing across capacitor 65.

This voltage across resistor 95 is applied through the connections previously pointed out between the base and emitter of transistor 66. As a result of the application of this negative voltage between the base and emitter, a cur rent is caused to how (in the electron sense), from the negative bus 87 through resistor 97, conductor 96, the collector and emitter of transistor as, conductors 9d, 77, 76, and diode 75 to the positive bus conductor 86. The passage of current through the collector-emitter path of transistor as causes the lower terminal of resistor 97 to become more positive with respect to the upper terminal. This voltage across resistor 97 is applied between the base and emitter of a further transistor 99, this transistor being of the NPN type. It will be noted that the upper terminal of resistor 97 is connected through the negative bus conductor 87 and conductor 180 to the emitter of transistor 99 while a lower terminal of resistor 97 is connected through resistor 161 to the base. A capacitor 192, connected between the base and emitter is effective to by-pass any transient voltages that may be present in the voltage across transistor 97.

Since, as pointed out above, the lower terminal of resistor 97 becomes possible with respect to the upper terminal upon transistor 66 conducting, it will be obvious that the connections just traced are effective to cause the base of transistor 99 to become positive with respect to the emitter and to cause the transistor -9 to become conductive. The current flow may then be traced (in the electron sense), from the negative bus 87 through conductor the emitter-collector path of transistor 99, a capacitor 18 3, and resistors 1%, Hi5, and 1% to the positive or grounded bus conductor 86. it will be noted that the resistor N36 is actually a rheostat having a movable slider 107 for shorting out variable portions of the resistor to change its effective resistance value. The function of this rheostat will be discussed in a moment.

The electron cur-rent flow through the path just traced causes the upper terminal of resistor 105 to become negative with respect to the lower terminal of resistor 106. It will be noted that the upper terminal of resistor MP5 is connected to the base of a further PNP transistor 110, the collector of which is connected through conductors 111, 94, 77, and 76, diode 75, and bus conductor 86 to the lower terminal of resistor 196. Thus, the effect of the current flow through the emitter-collector path of transistor 99, which causes a voltage to appear across resistors 1&5 and 1%, the polarity of which is such that the upper terminal of resistor 195 is negative with respect to the lower terminal of resistor 106, causes the base of transistor 110 to become negative with respect to the emitter to cause transistor 110 to in turn become conductive. It will be noted that the emitter-collector paths of transistors 66 and 110 are connected in parallel. The pulse initially applied to the base of transistor 66 is of very short duration and as soon as this ceases, transistor 66 ceases to conduct. In the meantime, however, transistor 110 becomes conductive in the manner just recited so that the circuit previously traced through the emitter-collector path of transistor 66 still remains energized.

In tracing the circuit through transistor 99, it will be noted that the circuit was traced through a capacitor 103. Connected in parallel with capacitor 103 is one or more of a plurality of capacitors 114, 115, 116 and 117. All of these capacitors have their upper terminals connected together and to a conductor 118 which is connected through a further conductor 119 to the upper terminal of capacitor 163. Each of the lower terminals of capacitors 11 i, 115, 116 and 117 are connected to contacts which are adapted to engage a conductive sector bar 121 carried by a rotatable insulating support member 122 which is positioned by a shaft 123 to which is secured the range selector knob 51. Also engaging the conductive sector bar 121 is a further contact 124 which is connected through a conductor 125 to the lower terminal of capacitor 103. in the position of the shaft 123 shown in the drawing, the sector bar 121 is in a position in which the lower terminals of all of the capacitors 114, 115, 115 and 117 are connected through the sector bar 121 and contact 124 to conductor 125 leading to the lower terminal of capacitor 1%. Thus, all four of the capacitors 114 through 117 are connected in parallel with capacitor 103. As shaft 123 is rotated in a counter clockwise direction, the conductive sector bar 121 successively passes from beneath the sliding contacts associated with capacitors 1E7, 116, 115 and H4 respectively. As the sector bar passes beneath the movable sliding contact associated with any one capacitor, that capacitor is effectively removed from the circuit. Thus, the rotation of shaft 123 through actuation of the range selector knob 51, is etiective to vary the number of the capacitors 114 through 117 in parallel with capacitor 103 and hence to vary the total capacitance of the circuit traced through transistor 99.

It will be noted that in the circuit traced through transistor 99, a portion of the circuit included the capacitor 1% and, as just explained, one or more of the capacitors 114 through 117. In addition, this circuit also included resistors 104, and the variable part of resistor 106. Thus, this circuit is a resistance capacitor circuit and, as is well understood, the charging time of the capacitors depends upon the time constant of the circuit which, in turn, is dependent both upon the values of the resistance and the total capacitance in the circuit. As has just been pointed out, it i possible to vary the capacitance in distinct steps by actuation of the knob 51 to in turn vary the number of the capacitors 114 through 117 in parallel with capacitor Hi3. As will be explained later, the range selector knob 51 is actuated to make major changes in the time constant or" this circuit and the delay produced by the delay unit.

The rheostat comp-rising resistor 106 and sliding contact 197 is provided for the purpose of adjusting the amount of the advance or delay that is desired. The slider 167 is connected by a shaft 126 to the ignition adjusting knob 52. By adjusting this knob, the slider 107 has moved up and down resistor 1% to vary the resistance in the RC circuit to inturn vary the time constant and the time during which it takes to charge the capacitors.

As soon as the capacitors in the circuit, whether they consist only of capacitor 103 or all of the capacitors 163, 114, 115, 116 and 117, are charged to a predetermined extent, current will cease to flow through resistor-s 1G5 and 106 in any substantial amount. Consequently, the voltage drop across these resistors will substantially disappear and the base or" transistor will again approach the positive potential of ground conductor 86. As was mentioncd above, the effect of rectifier 75 which, it will be noted, is connected between the emitters of both transistors 66 and 110 and the positive ground conductor 86 is to maintain the emitters of transistors 66 and 110 slightly negative with respect to the ground bus conductor 86. This helps to cut off these transistors when the voltage applied to the base disappears.

With both transistors 66 and 110 in a nonconductive state, the voltage drop previously discussed across resistor 7 disappears and a voltage is no longer applied between the base and emitter of the NPN transistor 99. Hence, this transistor ceases to be conductive.

It will be noted that adjacent the lower terminal of resistor ,7, there is shown a voltage wave designated by the character 127. It will be noted that this voltage wave initially rises abruptly and then gradually falls off reaching a minimum value at which point it drop-s abruptly to the base value. This depicts the voltage appearing at the lower end of terminal $7 with respect to the ground conductor 86. Normally the point at the lower end of resistor 9'7 is at a negative value depicted by the base line of the voltage wave 127. As soon as transistor 66 becomes conductive, however, the terminal at the lower end of resistor 97 approaches a potential of the positive bus condnctor 86 and hence becomes more positive. As the capacitor 103 and the connected capacitors 114 through 117 become charged, the voltage across resistors 105 and 106 begins to fall off, thus decreasing the amount of current through transistor 110. Thus, the voltage at the lower terminal of resistor 97 begins to fall off. This continues until a point is reached at which transistor 110 is abruptly cut off at which point the voltage drops back to the base voltage indicated.

The numeral 132 is employed to designate the representation of the wave form of the voltage that exists at the collector terminal of transistor 99. The base line voltage of this voltage representation 132 represents the voltage existing when the transistor 99 is nonconductive. As soon as the transistor 99 becomes conductive by reason of the voltage appearing across resistor 97 because of first transistor 66 and then transistor 11% becoming conductive, the impedance of the emitter-collector circuit of transistor 99 drops abruptly and the collector potential moves to a point much closer to that of the negative bus condoctor 87. Hence, as depicted by voltage wave 132, there is an abrupt decrease in the magnitude of the voltage. This decrease remains relatively constant until the transistor 110 is cut off as a result of the charging of the capacitors as previously explained. At this time, transistor 99 is abruptly rendered nonconducting and the voltage again resumes the value of the base line of the voltage curve. The width of this negative voltage pulse is indicative of the time delay that has been introduced by the resistance of the capacitor charging circuit which has just been described. This period of delay can obviously be adjusted both by adjusting the number of capacitors 114 through 117 in the circuit and by adjusting the setting of the rheostat comprising resistor 106 and slider 107.

When transistor 99 is cut off, the potential of the emitter as just described suddenly increases in a positive direction, as just described. In other words, the potential of i the collector with respect to the emitter suddenly be comes more positive. This positive voltage is applied between the base and collector of a further NPN transistor 135. It will be noted that the emitter of transistor 99 is connected to the emitter of transistor 135 through the negative ibus conductor 87 and a conductor 136. The collector of transistor 99 is connected through conductors 119 and 137, capacitor 138, diode 139 and resistor 140 in parallel and resistor 141 to the base. The sudden increase in potential due to transistor 99 becoming nonconductive passes through the capacitor 138 and causes the transistor 135 to become conductive. Current may now flow in the electron sense from the negative bus conductor 87 through conductor 136, the emitter and collector of transistor 135, capacitor 142 and resistor 143 to the positive bus conductor 86. Since capacitor 142 is at this time discharged, it offers no impedance to the flow of current and the result will be that a voltage drop will appear across resistor 143 so that the upper terminal of this resistor becomes negative with respect to the lower terminal. This voltage appearing across resistor 143 is in turn impressed between the base and emitter of a PNP transistor 146. A capacitor 144 is connected between the base and collector of transistor 146 to bypass any high frequency transients. It will be noted that the upper terminal of resistor 143 is connected through a resistor 145 to the base of transistor 146 whereas the lower terminal of resistor 143 is connected through positive bus conductor 86, diode 75 and conductor 147 to the emitter of transistor 146. The effect of these connections is that a negative voltage is applied to the base of transistor 146 and since this is a PNP transistor, the transistor will be rendered conductive to cause current flow from negative bus 87 through resistor 148, a diode 149, resistor 150 (and also through a resistor 151), the collector-emitter path of transistor 146, conductor 147, and diode 75 to the positive bus conductor 86. The result of this happening is that. current flows through both resistors 148 and 151 causing the lower terminals of both resistors to become positive with respect to the upper terminals. The positive voltage appearing across resistor 148 is applied between the base and emitter of the transistor so as to continue to maintain this conductive. It will be obvious that the voltage initially rendering this transistor conductive, being supplied through the capacitor 138, will be of relatively short duration and were it not for the feedback voltage supplied by reason of transistor 146 becoming conductive, transistor 135 would very shortly become nonconductive. Since, however, the voltage drop appears across resistor 148 before transistor 135 would otherwise have a chance to become nonconductive, this transistor remains conductive until the charging of the capacitors in the RC circuit, to be presently described, is completed.

In tracing the circuits through the collector-emitter path of transistor 146, a path was traced through a diode 149. This is present to prevent there being a low impedance path for the positive pulse which is applied to the base of transistor 135 to make it conductive. If it were not for this pulse, resistors 158 and 151 would provide a low resistance path to the negative bus 87 and relatively little of the pulse would be applied to the base of transistor 135.

Again, as with transistor 99, a circuit was traced and described in the conducting path of transistor 135, through a capacitor. In the present case, the capacitor is capacitor 142. This capacitor 142 may have connected in parallel therewith any one or more of four capacitors 155, 156, 157 and 158. These capacitors correspond in function to capacitors 114 through 117, previously described. The upper ends of all of these capacitors are connected together and to a conductor 160 which extends to the right-hand terminal of capacitor 142. The lower terminals of each of the capacitors 155 through 158 are each connected to a separate sliding contact engaging a conductive sector member 161 mounted on an insulating support member 162 which, in turn, is secured to the shaft 123. It will be readily apparent that actuation of the range selector knob 51 simultaneously moves both sectors 121 and 161. Cooperating with the sector bar 161 is a further contact 164 which is connected by conductors 165 and 166 to the left-hand terminal of capacitor 142. It will thus be readily apparent that depending upon the position of the range selector knob 51, one or more of the capacitors 155 through 158 are connected in parallel with capacitor 142. Since the circuit traced through transistor 135 also included resistor 143, it will be apparent that the circuit through this transistor is an RC circuit, the capacity of which is adjustable. In the previous RC circuit, the resistance was also adjustable. In the present case, this is unnecessary since the total time delay is the sum of the time delays produced by the two RC circuits and if one of them is adjustable, it is possible to obtain a sufiicient variation in the timing to take care of the desired lag or lead in the ignition timing. As will be pointed out later in connection with the overall operation, the capacitors selectively controlled by the range selector knob 51 are primarily for the purpose of selecting between dillerent types of engines or different speeds. For example, in an eight-cylinder engine, there is a 45 degree phase difference between the pulses whereas in a fourcylinder engine, there is 90 degree phase displacement. The engine speed obviously also affects the time spacing between the ignition pulses. The rheostat comprising resistor 1116 and slider 157, on the other hand, is employed once the system has been set for a particular engine and speed to advance or retard the ignition through the desired angle.

Going back to the circuit existing through transistor 135. current continues to flow through the path just traced including capacitor 142 and one or more of the capacitors 155 through 158 until these capacitors become substantially charged. By this time, the current flowing through resistor 143 drops to a minimum value so that the voltage drop across this resistor ceases to be substantial. Under these conditions, there no longer is an appreciable negative voltage being applicd to the base of transistor T46 and this transistor ceases to conduct. When this happens, the current flow through resistor 148 ceases and since the original voltage initiating the conductivity of transistor 135 ceases to exist due to the blocking action of capacitor 133, transistor 135 will now become abruptly nonconductive. The period of time in which transistor 135 was conductive is dependent upon the time constant of the RC circuit which, in turn, is dependent upon the number of capacitors connected into parallel with capacitor 142.

The numeral 156 is employed to inti'caie a voltage wave depicting the voltage existing at the collector of transistor 135 with respect to the ground. conductor 86. initially, when the transistor 135 is nonconductive, the voltage at the collector is closer to the potential existing at the grounded positive bus conductor 86. As soon, however, as transistor 135 is rendered conductive in the manner described above, the collector-emitter voltage drops abruptly and the collector voltage moves in the direction of the potential existing on the negative bus conductor 87. As soon as transistor 135 is rendered nonconductive, the potential of the collector of transistor 135 again assumes the base line voltage.

In the voltage wave indicated by the reference numeral 156', l have shown the collective delays introduced by both the two RC circuits. The initial wave, bounded on one side by a solid line and on the right-hand side by a dotted line, is that introduced by the first RC circuit including transistor ")9. it will be recalled that soon as this transistor cuts oil, the second transistor r35 becomes conductive so as to continue the voltage at a reduced value. When this cuts oil, the voltage again resumes the base line value, it will thus be apparent from the dotted line indication that the total delay introduced into the voltage wave represented by numeral 156 is an accumulation of two delays. one of which is determined by the time constant of the circuit including transistor 99 and the her of which is determined by the time constant of the circuit including transistor 135,

The use of two timing circuits not only has the advantage of making possible a longer time delay without the use of capacitors of exceptionally large size but it also makes it possible to have a time delay greater than the time period between successive pulses. If a single timing circuit were employed and it was attempted to have a time delay greater than the time delay between pulses, the next pulse from secondary winding 11 would be applied to the input of the timing circuit before the timing cycle had been completed. This would obviously ail ect the operation of the timing circuit. With the present circuit, however, the timing action of the first stage of the timing circuit is compleie-d before the next pulse is applied to the timing circuit. Thus the first stage of the timing circuit can be per-forming its timing action While the second stage is still completing the timing action resulting from the first pulse.

As was pointed out in connection with FIGURE 1, there is a timing selector in which there is a knob 176 movable in a slot 177'. The knob 176 controls a switch 178 having a movable switch blade 179 movable between two fixed contacts 180 and 181. When it is desired to remotely control the ignition, the knob 176 is moved from the position shown, identified as the Car Position, to the Remote Position. This causes movement of switch blade 179 from the position shown in which it is in engagement with fixed contact ltlil to a position in which it is in engagement with fixed contact 131. When this happens, a circuit is completed from the collector of transistor 135 throu h conductor 166, fixed contact 1 31, switch blade Z179, conductor 182, capacitor 183, conductor 184, and resistor 185, to the control grid of a gas-filled tube 135. This gas-filled tube is employed to control the encraizallon of the auxiliary coil ill as will be presently escribed.

Gas-filled tube 1% comprises a cathode 189, filament heater 198 for heating the cathode, the control grid 191, a screen grid 192, and the anode 193. The screen grid 192 is connected to cathode 139 by conductor 187. The control grid 191 is normally biased negatively by a voltage derived from a resistor 195 connected across the terminals 78 and 7% of the power supply 67. Cooperating with this resistor 95 is a slider 1% which is connected through resistor to the cont-rel grid 191. The positive side of resistor U5 is connected through conductors 197 and 198 to the cathode 189. The slider acts to tap oii a variable portion of the voltage appearing between output terminals 78 and '79 of the power supply 67 and to apply a selected negative biasing voltage to control grid 191.

The anode-cathode voltage of the gas-filled tube 1% is derived from a second power supply 193, the input termirials of which are connected across the terminals of the secondary winding 72 previously referred to. Like power supply 6",", power supply 1% is provided with suitable rectifying and filtering means so that a relatively smooth filtered DC. voltage appears between the positive output terminal 199 and the negative output terminal Elli? of power supply 198. The positive output terminal 199 is connected through resistor .261 to the anode 193. The negative terminal 2% is connected through conductor 1% to the cathode. The primary winding 41 of the ignition coil 40 is connecLcd between the anode 193 and the oath ode 189 by a capacitor Zil-i and conductor 1S7. Capacitor 2th; is maintained in a charged condition when tube 186 is not firing by a circuit extending from the negative side or: the power supply 198 through conductors 96 and 137, primary winding 41, capacitor 2G4, and resistor 231 to the positive terminal of power supply 193.

As previously pointed out, the voltage appearing at the collector of transistor 135 is impressed upon the control grid 191 of gas-filled tube E86. At the end of the delay period, as will be noted from the voltage wave 356, the collector voltage suddenly rises and this sudden change of voltage is passed through capacitor 183 to the grid 191, raising the potential of the grid B1 to cause firing of the tube 136 Due to the action of capacitor 183, the voltage is applied to grid 191 for only a very short period of time but this is sulficient to cause the tube to fire and cause the capacitor 204 to discharge through primary winding 41 and the cathode anode path of tube 186. The sudden flow of current through primary winding 41 causes a voltage pulse to be produced in the secondary of ignition coil 40 where it is applied to the distributor in the manner pointed out in connection with FIGURE 1.

Where the timing selector is in the position shown in FiGURE 5 in which the knob 176 is in the Car Position, the voltage pulse applied to the control gridwl is that appearing at the collector terminal of transistor 66, which voltage pulse has had none of the delay introduced into it by the two RC circuits. Thus, the voltage pulse at this point is in phase with the voltage pulse produced by the breaker switch blades 20 and 21. Thus, the timing selector gives the mechanic an opportunity of initially first fired directly by the pulse from the breaker contacts checking the operation by having the gas-filled tube 186 and then fired by the delayed pulse.

The meter 50 has been referred to as indicating the amount which the ignition is advanced or retarded. The means by which this meter 5 indicates this will now be described. The right-hand terminal of meter 54) is effectively connected to a voltage divider including resistors Zlil, 211. and 212, which are connected in series between the negative bus conductor 87, through conductors 2 513 and 83, and the positive bus conductor 86 through conductor 76 and rectifier 75. The right-hand terminal of meter 50 is connected to the junction of resistors 21 and 211, and hence is maintained at a potential depending upon the relative value of resistor 21th with respect to that oi": resistors 211 and 2E2. Resistor M2 is a rheostat having a slider 21 i movable over the resistor 212 and connected 13 to the right-hand terminal of resistor 212 so as to short out a variable portion of the resistor. The slider 214 is positioned by knob 53, which is referred to in connection with FIGURE 1 and which is a meter adjustment knob. The effect of adjusting slider 214 will be referred to in more detail presently.

The left-hand terminal of meter 50 is connected to an intermediate point in another vo'tage divider arrangement which is somewhat more complex, and will be briefly described here and described in more detail in connection with FIGURE 6. In the first place, the left hand terminal of meter 50 is connected through conductors 215 and 216, a resistor 217, and conductors 137 and 119 to the collector of transistor 99. The left-hand terminal is also connected through a conductor 218, and a resistor 219 to the collector of transistor 135. It will be recalled that in the case of both transistors 99 and 135, the emitter-collector path of the transistor was connected in series with a resistant capacitive network which determined the time delay. The duration of current flow through resistors 217 and 219 is thus dependent upon the time during which transistors 99 and 135 are conductive, and hence upon the length of the timing periods. The left-hand terminal of the meter 50 is also connected to the ground or positive bus conductor 86 through a capacitor 220and a resistor 221 connected in parallel with each other. The resistor 221 is provided with a slider 222, con nected to the left-hand terminal of resistor 221. As pointed out above, the operation of the meter can best be understood by reference to FIGURE 6 in which the elements connected to the meter and controlling its energization have been somewhat rearranged physica'ly, although in the same positions electrically, and have been shown by themselves without other elements having no appreciable effect upon meter 50. From this figure, it is readily ap parent that the two input terminals of meter 59 are connected in what amounts to the output terminals of a somewhat complicated bridge. In one arm of this bridge, there is a fixed resistor 211 and the adjustable resistor 212. In the lower right-hand arm of the bridge, there is a fixed resistor 210. In the upper left-hand arm of the bridge, there are the emitter-collector paths of the two transistors and the two resistors 217 and 219 in series therewith. In the lower left-hand arm of the bridge, there is a variable resistor 221 and a capacitor 220 in parallel therewith.

From an examination of FIGURE 6, it will be readily apparent that the right-hand terminal of the meter is at a potential dependent upon the relative adjustment of the slider of resistor 2 12. The left-hand terminal is maintained at a potential dependent upon the delay which my delay unit is introducing and is set to maintain. During the period when transistor 99 is turned on, current will flow, in an electron sense, from negative conductor 87 through conductor 100, the emitter and colector of transistor 99, resistor 217, conductor 216, and capacitor 221) and resistor 221 in parallel. During the delay period in which transistor 135 is turned on, current will flow from negative conductor 87 through conductor 136, the emittercollector path of transistor 135, resistor 219, and the capacitor 220 and resistor 221 in parallel.

The capacitor has a relatively high capacitance and tends to integrate the current flow that has taken place through resistors 217 and 219. Actually, current flow takes place through these resistors over most of the time. Where the delay unit is set to maintain a delay period which is exactly equal to the time between pulses, it will be apparent that as soon as transistor 135 is turned ofl, transistor 99 is turned on so that one or the other of the transistors is continuously conductive so that current is supplied continuously to capacitor 211 and resistor 221. Where the delay time is greater than the interval between pulses, there actually is no time during which current is not flowing through one or the other of transistors 99 and 135 and, as a matter of fact, current flows through transistor 99 while current is still flowing through transistor 135. The only time that current does not flow through one or the other of the transistors is when the apparatus is set to advance the ignition and during a period of time dependent upon the amount of the advance, no current flows. This, however, is a relatively short period of time and the capacitor 229 is capable of smoothing out any irregularities in the voltage across resistor 221 due to the absence of current during these short periods.

As will be readily apparent, the longer the delay time, the more the total current flow through capacitor 220 will be and the higher the charge it will assume. Consequently, the left-hand terminal of meter 50 will become more negative. On the other hand, the shorter the delay time, the less total current will flow through capacitor 229 and there will be a smaller charge so that the left-hand terminal of the meter will be less negative. Thus the current flowing through meter 50 is an indication of the delay time.

The sensitivity of the meter is adjusted by slider 222. Since resistor 222 is in parallel with capacitor 220, it is obvious that the time required for capacitor 220 to assume any charge depends upon the value of resistor 221 which provides a discharge path for condenser 229. Thus, the smaller the amount of resistor 221 connected in parallel with capacitor 226, the smaller will be the voltage developed across capacitor 220 during any period of time during which transistors 99 or are conductive.

The meter actually indicates the amount of delay time with reference to the time existing between pulses. If the meter 59 is to indicate the amount that the ignition is advanced or retarded, the information that is really signiflcant is the amount that the ignition is advanced or retarded with respect to the normal time between pulses. Obviously, if the delay time is exactly equal to the time between any two pulses, there has been no change in the timing as far as the engine is concerned.

When the delay time is exactly equal to the time between pulses, that is, when there is no effective retarding or advancing of the ignition, one or the other of the two transistors 99 and 135 is conducting all the time. In other word, the voltage wave form 15 6' of FIGURE 5 is exactly equal in length to the distance between pulses and this voltage pulse is composed of two pulses, one produced by the delay time introduced by the RC network associated with transistor 99 and the other the delay time introduced by the RC network associated with transistor 135. The apparatus is designed so that under these conditions, the potential of the two points in the network to which the right and left-hand terminals of meter 50 are connected will be the same. Means are provided for checking this.

Referring to FIGURE 5, it will be noted that there is a switch 235 which is controlled by the push button 55, referred to in connection with FIGURE 1. When button 55 is actuated, switch 235 is closed. Switch 235 is connected across the rectifier 139, which is connected between the transistor 99 and the base of transistor 135. As long is switch 235 is open, it is possible to have an overall delay time that is greater than the time between two pulses. It will be recalled that in the operation previously described, the completion of the charging of the capacitance in the RC circuit associated with transistor 9-9 caused, through the cutting oif of transistor 11%, a sudden cutting oif of transistor 99 so that there is a rise in potential of the collector of transistor 99 which is transmitted through to the base of transistor 135 to turn this transistor on. If the slider 1tl7, associated with resistor 106, is so set as to provide such a long time constant for the RC circuit associated with transistor 99 as to retard the ignition, that is, to have a total overall timing period greater than the time between pulses, then it is obvious that before transistor 1 35 has been truned off, a new pulse will be received at the base of transistor 66. This will, in

turn, cause a voltage drop across resistor 97 to, in turn, turn on transistor 99. This, in turn, turns on transistor it it were not for the reciifier 139 and the resislor 14*, this sudden decrease in the potential of the collector of transistor 99 would lower the potential of the base and turn the transistor oil. again. Because of the diode 139 and the resistor 14 0, the negative voltage pulse produced by transistor 90, again becoming conductive, is not capable of turning off transistor 135 since this negative pulse is blocked by a diode 3139. If, however, the button is actuated to close the switch 235, the diode 1.39 is shunted so that this negative pulse is able to pass through to the base of transistor 135 and to turn off transistor 135 just as though its RC circuit had been fully charged. Thus, the timing cycle will be ended abruptly with the new pulse reaching the base of transistor 66. Under these conditions, the overall length of the delay becomes exactly equal to the length of time betwen pulses.

The switch 235 and button 55, through the action described above, provides a means for calibrating the meter. If the button 55 is depressed to close switch 235, the pointer of meter 50 should be at the zero point. If it is not, it is possible to adjust knob 53 to adjust the rheostat 21.2 to vary the potential on the right-hand side of the meter until the pointer comes to zero. After this, the button 55 can be released and it is assured that the meter Will correctly indicate the amount that the ignition has been advanced or retarded.

All of the above description has been with the assumtion that the meter is used with one particular engine and at one speed. Let it be assumed, however, that the meter has been used with a four-cylinder engine and it is now desired to use it on an eight-cylinder engine. Under these conditions, the phase angle through which the ignition must be retarded in order to have no shift in timing of the ignition is 45 degrees rather than 90 degrees. The knob 51 is accordingly adjusted to vary the number of capacitors 114 through 117 and 155 through 153, which are connected into the circuit. Under these conditions, the delay time collectively introduced by the two timing circuits in my apparatus will be approximately 45 degrees. Depending upon the setting of slider 1G7 and resistor 106, this delay may he more or less than 45 degrees. The actual time will, of course, depend upon the engine speed which is pro-selected and is a factor in detel-mining the setting of knob 51. Assuming that slider 107 is set so as to maintain the same delay as exists between pulses, it will be obvious that just as when there was a 90 degree distance between pulses, either transistor 99 or transistor 135 will always be conductive so that even though the delay time is now only half what it was before with a four-cylinder engine, the total amount of time the current is flowing through capacitor 220 due to transistor 09 or 135 being conductive, will be the same. Similarly, if the engine speed is changed, the necessary delay time in terms of actual seconds is changed but the frequency of the pulses is correspondingly changed so that again for a condition in which there is no retarding or advancing of the ignition, the total energization of capacitor 220 will remain the same so that the meter will remain in the zero position when the slider 107 is set for either advancing or retarding the ignition, it will be obvious that the voltage existing across capacitor 220 is correspondingly changed just as was described above.

While my invention is not limited to using components having any particular values, I did employ in one particular embodiment components having the following values:

Transistors es, 110 and 146 2N59'1 99 and 135 2-N35 Tubes A86 .a Type 2050 Transformer 69 Winding 68 v 20 inding 72 v 600 Winding 70 v 110 Capacitors 6d rnicrofarad 220 .01 .01 .1 .1 .2 .47 1.0 .01 .1 002 .1 156 do .2 157 d0 .47 1 50 do 1.0 18 do .005 204 do 2.0 220 do 2000.0

Resistors 62 kilohms 6.8 63 d0 6.8 do 560 92 ohms 22 95 kilohms 27 7 ohms 270 1.01 do 105 kilohms l 306 do 5 do 82 141 do 2.7 143 do 5 1.45 do 5.6 148 do 2.7 150 0hms 150 151 do 470 1.85 kilohms 56 1% megohrns l 201 ohrns 2000 210 do 27 211 do 590 2.12, do 500 217 do 470 219 do 470 221 do s 50 OPERATION It is believed that the overall operation is apparent from the foregoing description. It will, however, be briefly re viewed in the following paragraphs.

When it is desired to test the timing to determine whether the timing is properly set, the normal connection between the ignition coil and the distributor is interrupted and the output of the normal ignition coil is connected to the input of my delay unit. The auxiliary ignition coil 40 connected with my unit is connected to the distributor 15. The apparatus is then turned on by closing the on-off swi'ch 55. By examining a chart which may appear on the front of the meter, the knob 51 is set to a position dependent upon the number of cylinders of the engine being tested and the speed which it is desired to maintain while the test is being run. The slider 107 is then set to provide for the ignition being retarded somewhat. A button 55 is then pressed and it is observed whether the pointer of meter 50 goes to Zero. If it does not, the meter adjusting knobs 53 is turned until it does go to zero. The apparatus is now ready for operation.

in the manner pointed out above, each pulse received from ignition coil 13 starts a series of two sequential timing operations which collectively produce a time delay which may be the same as, adjustably more than or adjustably less than the time normally existing between two pulses. The delay pulse is then supplied by the ignition coil to the distributor where it is applied to the proper spark plug. By adjusting knob 52, a desired degree of advancing or retarding of the spark can be obtained. This, moreover, is accomplished by adjusting a knob on a control box which need not be in the engine compartment at all. The performance of the engine for different settings of the ignition can be observed by suitable testing equipment and it can be determined what is the optimum setting of the ignition timing.

Thereafter, the apparatus can be disconnected and while the engine is stationary or idling, the distributor can be adjusted to provide the timing adjustment which has been determined by the apparatus to be the opiimum.

CONCLUSION It will be seen that I have provided a novel ignition timing control apparatus in which it is possible to readily adjust the ignition timing from a remote point.

It will further be seen that I have provided a novel form of delay circuit of general application for adjustably varying the delay for which a series of pulses are subjected so that the pulses are delayed either more or less than the time spacing between these pulses.

While I have described a specific embodiment of my invention for purposes of illustration, it is to be understood that the scope of my invention is limited solely by the appended claims.

I claim as my invention:

1. Ignition timing control apparatus for use with an internal combustion engine having means for producing voltage pulses in selectively timed relation to the operative position of the engine elements, a plurality of igniting devices, and distributor means for selectively and suc cessively applying said voltage pulses to said igniting de vices;

said apparatus comprising an adjustable delay device having an input and an output,

means for connecting said input to such an abovenamed means for producing voltage pulses,

and means for connecting said output to such an abovenamed distributor means, 7

said delay device being capable of delaying said voltage pulse by an amount of time comparable to that normally existing between said pulses so that the pulse applied to any one igniing device is produced as a result of a pulse intended for the preceding igniting device, and said delay device including means for adjusting the extent of said delay over a range extending from less than to greater than the period or" time between pulses so that the voltage pulse applied to any one igniting device may be selectively advanced, in phase with, or retarded with respect to the time at which a pulse would normally be applied to said igniting device.

2. The apparatus of claim 1 in which there is a switching device independent of said adjusing means for calibrating purposes and circuit connections from said switch ing device to said delay device effective when said switch is actuated to cause the length of said delay to equal exactly the length of time between pulses regardless of the setting of said adjusting means.

3. Ignition timing control apparatus for use with an internal combustion engine having means for producing voltage pulses in selectively timed relation to the operative posiion of the engine elements, a plurality of iguiting means, and distributor means for selectively and successively applying said voltage pulses to said igniting means;

said apparatus comprising an adjustable delay device having an input and an output,

means for connecting said input to such an abovenamed means for producing voltage pulses,

an auxiliary means forp roducing voltage pulse having its input connected to the output of the adjustable delay device and effective to produce a voltage pulse each time that a predetermined voltage change occurs at the output of said delay device as a delayed result of a voltage pulse being applied at the input of said delay device,

and means for connecting the output of said auxiliary pulse forming means to such a distributor means,

said delay device being capable of delaying said voltage pulse produced by said auxiliary pulse producing means with respect to the initiating pulse of said normal pulse producing means by an amount of time comparable to that normally existing between the pulses produced by said normal pulse producing means so that the pulse from said auxiliary pulse forming means applied to any one igniting device is produced as a result of a pulse intended for the preceding igniting device,

and said delay device including means for adjusting the extent of said delay over a range of time extending from a value less than to a value greater than the period of time between pulses so that the voltage pulse applied to any one igniting device may be selectively advanced, in phase with, or retarded with respect to the time at which a pulse would normally be applied to said igniting device.

4. Ignition timing control apparatus for use with an internal combustion engine having means for producing voltage pulses in selectively timed relation to the operative position of the engine elements, a plurality of igniting devices, and distributor means for selectively and successively applying said voltage pulses to said igniting devices;

said apparatus comprising an adjustable delay device having an input and an output,

means for connecting said input to such an adjustable delay device for producing voltage pulses at the output thereof,

and means for connecting said output to such an abovenamed distributor means,

said delay device having adjusting means and being capable of delaying said voltage pulse by an adjustable amount of time comparable to that normally existing between said pulses so that the pulse applied to any one igniting device is produced as a result of a pulse intended for the preceding igniting device,

said delay device including an indicator for indicating whether the delay time is equal to or ditlerent from the period of time between pulses,

and calibrating means independent of said adjusting means for checking the operation of said indicator,

said calibrating means being effective when operated to terminate the period of delay regardless of the setting of the adjusting means when the next succeeding pulse is produced by said pulse producing means so that the total period of delay exactly equals the period of time between pulses.

5. Ignition timing control apparatus for use with an internal combustion engine having means for producing voltage pulses in selectively timed relaion to the operative position of the engine elements, a plurality of igniting devices, and distributor means for selectively and successively applying said voltage pulses to said igniting devices;

said apparatus comprising an adjustable delay device having an input and an output,

19 20 means for connecting said input to such an above- 6. The timing control apparatus of claim 5 in which named means for producing voltage pulses, there is means for adjusting the timing periods of both and means for connecting said output to such an abovetimers simultaneously and means for independently adnanied distributor means, justing the timing period of one of said timers.

said delay device being capable of delaying said 5 voltage pulse by an amount of time which may R f r n s Cited be adjusted over a range extending from a value UNITED STATES PATENTS less than to a value greater than that normally 2,785,215 3/1957 Yeuer 324 16 existing between said pulses so that the pulse ap- 3,078,391 2/1963 Bunodiere 123-148 plied to any one igniting device 15 produced as 10 3,264,521 8/1966 Huntzinger 315-209 a iesult of a pulse intended for the preceding igniting device, 3,277,875 10/1966 Miki 315-209 and said delay device comprising two sequentially 3286164 11/1966 Huff 32416 operated timers, the first of which always completes its timing operation in a period of time 1 FOREIGN PAFE NTS less than the time between successive pulses and 849,444 9/1960 Great Bntamis capable of performing a timing operation initiated by the next succeeding pulse while the RUDOLPH ROLINEC Pnmal'y Exammm" second timer is still completing its timing action M, J, LYNCH, Assistant Examiner.

as a result of the first timer having completed 20 its initial timing action. 

